The Spider-Slayer Robot was the invention of Professor Spencer Smythe. Professor Smythe was an expert in the field of robotics as well as very knowledgable in the realm of arachnids or spiders. Smythe decided to marry these two passions in an unusual way, constructing robotic creations that did not benefit the study of spiders but rather were designed to seek out and destroy their subjects. One can only imagine that as a child Smythe over-empathized with Little Miss Muffett and cheered at the nursery rhyme the Itsy Bitsy Spider.

Smythe probably would have spent his days as a rather weird recluse with an unusual hobby were it not for the influence of J. Jonah Jameson, publisher and editor and chief of the Daily Bugle. Jameson possessed a rather deep seated hatred of the costumed hero Spider-Man and after seeing a demonstration of Smythe's work, paid him to construct a robot capable of capturing and killing Spider-Man. The result was a series of robots with a varying number of arms and abilities that were sent out to attack our hapless hero. On some ocassions, the robot was piloted remotely by Jameson himself so that he could view the destruction of his foe. To make sure that Spider-Man would see the source of his destruction, Smythe constructed a device that would allow Jameson's disembodied head to be viewed on the Spider-Slayer Robot (think Oz, the Great and Terrible and you will be on the right track).

Eventually, Smythe died as a result of numerous and prolonged exposure to radioactive material used as power sources for his various robots. Finding out that he was going to die, Smythe blamed Jameson and sought his revenge against both the publisher and Spider-Man by chaining the two together with a bomb. Spider-Man was able to disarm the bomb, but with Smythe's death it seemed that the Spider-Slayer Robot was gone forever.

A few years later, Smythe's son Allister sought his revenge against Spider-Man for his father's death by constructing his own Spider-Slayer Robot. Again, the robot and the hero fought with the robot eventually being destroyed.